How many of the following respiratory reaction occur in the cytoplasm of a eukaryotic cell ?
(1) PGAL `rarr` 1, 3 di PGA
(2) Succinyl CoA `rarr` Succinic acid
(3) Pyruvic acid `rarr` Acetyl CoA
(4) PEP `rarr` Pyruvate
(5) Fructose 1,6 diphosphate `rarr` DHAP + 3PGAL

Options

A. (1) and (5) only
B. (1), (4) and (5) only
C. (1), (2),(3) and (5) only
D. (1) and (5) only

Answer

To determine how many of the given respiratory reactions occur in the cytoplasm of a eukaryotic cell, we will analyze each reaction step by step:

1. **PGAL to 1,3-DiPGA**:
- This reaction is part of the glycolysis pathway, specifically during the payoff phase. Glycolysis occurs in the cytoplasm of eukaryotic cells.
- **Conclusion**: This reaction occurs in the cytoplasm.

2. **Succinyl CoA to Succinic Acid**:
- This reaction is part of the Krebs cycle (also known as the citric acid cycle), which takes place in the matrix of mitochondria, not in the cytoplasm.
- **Conclusion**: This reaction does not occur in the cytoplasm.

3. **Pyruvic Acid to Acetyl CoA**:
- This reaction is known as the link reaction, which connects glycolysis to the Krebs cycle. It occurs in the matrix of mitochondria.
- **Conclusion**: This reaction does not occur in the cytoplasm.

4. **PEP to Pyruvate**:
- This reaction is the last step of glycolysis, where phosphoenolpyruvate (PEP) is converted to pyruvate. Since glycolysis occurs in the cytoplasm, this reaction also occurs there.
- **Conclusion**: This reaction occurs in the cytoplasm.

5. **Fructose 1,6-diphosphate to DHAP + 3PGAL**:
- This reaction is part of the glycolysis pathway, specifically in the preparatory phase. Since glycolysis occurs in the cytoplasm, this reaction also occurs there.
- **Conclusion**: This reaction occurs in the cytoplasm.

Now, let's summarize the reactions that occur in the cytoplasm:
- Reaction 1: PGAL to 1,3-DiPGA (Cytoplasm)
- Reaction 2: Succinyl CoA to Succinic Acid (Not Cytoplasm)
- Reaction 3: Pyruvic Acid to Acetyl CoA (Not Cytoplasm)
- Reaction 4: PEP to Pyruvate (Cytoplasm)
- Reaction 5: Fructose 1,6-diphosphate to DHAP + 3PGAL (Cytoplasm)

**Total reactions occurring in the cytoplasm**: 3 (Reactions 1, 4, and 5).

### Final Answer:
**3 reactions occur in the cytoplasm of a eukaryotic cell.**